in vitro culture and isoenzyme analysis of giardia lamblia

Chapter 2
SAMPLE COLLECTION AND PREPARATION
2.1 INTRODUCTION
2.1.1 Sourcing And Harvesting of Cysts
In order to fulfil the aims of the present study, there was a need to obtain
trophozoites for in vitro culture initiation. There are two commonly employed
methods of obtaining trophozoites from infected persons. The first derives the
parasites by excystation of cysts that are excreted in faeces (Kasprzak and
Majewska, 1985; Isaac-Renton et al., 1986; Meloni & Thompson, 1987; AI-Tukhi
et al., 1991), while the second method involves the use of a gelatin string-capsule
(Enterotest) or intubation to obtain a duodenal aspirate containing the organisms
(Meyer, 1976, Gordts et al., 1984; Gordts et al., 1985). In vitro cultures of Giardia
trophozoites have been successfully initiated using both methods of recovery
(Gordts et al., 1985; Meloni & Thompson, 1987).
When 4 methods for detecting Giardia lamblia (namely examination of stools,
duodenal aspirates, intestinal biopsies and impression smears) were evaluated
(Kamath & Murugasu, 1974), parasites were detected by 1 or more of these
methods in 12 of 21 patients. The study showed that duodenal aspiration was
superior to faecal cyst detection. The former could detect the infection in 10 of the
12 Giardia infected patients (83% sensitivity), while triplicate stool examinations
detected infections in 6 of the 12 (50%) positive samples. (Kamath & Murugasu,
1974). Similarly, Ament & Rubin (1972) reported that Giardia was not detected by
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